Ipsec Header Options - Brocade Communications Systems StoreFabric SN6500B Administrator's Manual

15
IPsec concepts
FIGURE 41

IPsec header options

IPsec adds headers to an IP datagram to enable authentication and privacy. There are two options:
•
•
Authentication Header
AH can be used to authenticate a data stream, but does not provide encryption needed for privacy.
The AH contains a message authentication code (MAC). The MAC is created by a hash algorithm
calculation. The MAC is transmitted in an IP datagram. The same hash algorithm is then used by
the receiver to verify the integrity of the packet. AH can be used in either transport mode or tunnel
mode, as shown in
FIGURE 42
190
Transport mode and tunnel mode comparison
Authentication Header (AH)
Encapsulating Security Payload (ESP)
Figure 42.
AH header in transport mode and tunnel mode
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